WASHINGTON — Fourth graders in traditional public schools score better in reading and math than students in charter schools, according to a government report that is likely to spur a fresh debate over the benefits of school choice.

The report, released Tuesday, says fourth graders in traditional public schools scored an average of 5.2 points better in reading than students in charter schools on the National Assessment of Educational Progress test in 2003. Students in traditional schools scored an average of 5.8 points better in math.

The report cautions that the results could be influenced by factors other than the quality of charter schools.

"Parents may have been attracted to charter schools because they felt that their children were not well-served by public schools, and these children may have lagged behind their classmates," said the report by the National Center for Education Statistics, which is part of the Department of Education.

"On the other hand, the parents of these children may be more involved in their children's schooling and provide greater support and encouragement," the report said.

The agency studied fourth-grade math and reading scores at 150 charter schools and 6,764 traditional public schools, nationwide. The scores were from the 2003 NAEP, an assessment given to students across the country.

Charter schools are public schools that are sometimes run by private entities and are usually free of many of the regulations that govern traditional public schools. They have become popular in many areas where traditional public schools are struggling.

Supporters argue that charter schools improve public education by creating competition with traditional public schools. Opponents argue that charter schools drain resources from traditional public schools.

The report offered some good news for charter schools: Reading scores at charter schools in central cities serving mostly minority students were comparable to scores at traditional public schools. However, math scores at such charter schools still lagged behind those at traditional schools.